So-called LARP (“laser activated remote phosphor”) applications in which a phosphor volume is irradiated by means of a blue primary light emitted by a laser are known. The phosphor volume converts some of the blue primary light into yellow secondary light, as a result of which blue-yellow or white used light with a high luminance is produced. Such LARP arrangements are known for use in automobile headlamps.
On account of the high safety standards in the automotive sector, it is necessary to monitor reliably whether the wavelength conversion operates as expected or whether the direct, blue laser light can emerge from the LARP arrangement. If this is the case, the LARP arrangement can be dimmed or switched off entirely.